Pneumatic percussive apparatus.



H. C. BEHR.

PNBUMATIG PERcUssIvE APPARATUS. APPLIGATION FILED NOV. 9, 1910.

' Patented Apr. 30, 1912.

z SHEETS-SHEET 1 I I: (a I I I I l I l I I I I I I I I I l I I I I I v.A I 2 A l/I/Lbl/ COLUMBIA PLANOGRAPH C0., WASHINGTON. D.

H. c. BEER. PNEUMATIG PBROUSSIVE APPARATUS.

I APPLICATION ILED NOV. 9, 1910. 1,024,669.

Patented Apr. so, 1912.

lli Il lul' f l l l I L l l l lvlllw/IIIH l I l I l l I l l 2 Zu 2 2narran sirkras PATENT ormoni.

HANs CHARLES BEHR, or JoHANNEsBURe, TRANsvAAL.

PNEUMATIC PERCUSSIVE APPARATUS.

To all whom it may concern: p

Be it known that I, HANS CHARLES BEHR, consulting mechanical engineer, acitizen of the United States of America, residing at ConsolidatedGoldelds Buildings, Johannesburg, Transvaal, have invented new anduseful Improvements in Pneumatic Percussive Apparatus, of which thefollowing is a specification.

The present invention relates to pneumatically actuated stamps and otherpercus` sive machines, of the kind in which motion is transmitted from apositively reciprocated member to a percussive member by means of acushion or cushions of air, the pressure of which is always higher thanthat of the atmosphere. In such apparatus as heretofore known, a fixedcylinder has been employed in which worked two pistons, one of which wasreciprocated positively and the other of which formed part of thepercussive member. The cushion of air between the adjacent faces of thepistons propelled the percussive piston forward upon its working stroke,while the pressure for effecting the return of the percussive member wasafforded in some cases by an air cushion formed by making suitableconnections between the extreme faces of the pistons, or in other casesby a body of fluid kept at constantpressure or by a combination of bothsystems. In order to produce sufficiently positive transmission ofmotion during the working stroke it was necessary to have as small acushion as possible between the adjacent faces of the pistons, whichcondition however conflicted with the necessity of providing forvariation of the stroke of the percussive member due,

. for instance, to the presence under the stamp of larger or harderpieces of material than those for the reduction of which the stamp wasdesigned.

The present invention is illustrated in the accompanying drawings, inwhich- Figure I is a partly sectional elevation of a stamp constructedaccording to the invention; and Fig. II is a similar view of a modifiedconstruction.` p

According to this invention, one member is formed with a cylinder l andthe other with a piston 2 working therein. Either of such members may bearranged for positive reciprocation. Thus, in the construction shown inFig. I, the cylinder 1 is reciprocated by means of crank 3 andconnecting rod 4l, the piston 2 then forming part of the Specificationof Letters Patent.

Application led November 9, 1910.

`connections hereafter described.

Patented Apr. 30, 1912.

serial No. 591,480.'

percussive member. As shown in Fig. II, the stamp head 5 is formed atits upper end with a cylinder l within which works the piston 2 which'isreciprocated by the crank 3 and connecting rod 4.

Between the respective piston and cylinder faces 6, 7, which tend toapproach during the working stroke, is formed a chamber 8 within which abody of air is maintained at pressure higher than that of theatmosphere. For this purpose, an air compressor 9 supplies a receiver l0from which air is passed freely to the cylinder by the The pressure ofthe body of air in chamber 8 is constant apart fro-m such slightvariation as is due to some of the air having to flow in and out of thecylinder to and from the receiver l0 during the relative reciprocatingmovementof the piston and cylinder. Upon the opposite side of the piston2 is formed a chamber l1 inclosing a body of air. By the reciprocationof the positively reciprocated member such body of air is alternatelyrarefied and compressed, thereby giving rise to reciprocation of thepercussive member.

Both bodies of air contained in chambers 8 and 1l respectively, arepermanent in the sense that they are not successively fed in andexhausted; nor, in the preferred method of operation, are portions ofthem exhausted at intervals and replaced by fresh air to preventover-heating, as in some types. Once -t-he compressor 9 has initiallyfilled the receiver l0 and the chambers 8 and 11, its function is merelyto make up air lost by unavoidable leakage.

In practice, the mean relative position of vthe parts is so adjustedthat the body of air in chamber 8 is comparatively large and that inchamber l1 comparatively small. The

bounding faces 6 and 7 of chamber 8 being those which tend to approachduring the working stroke, their wide separationA obviates danger oftheir colliding during the working stroke; while on the other hand, thesmaller chamber l1 is, the greater becomes the variation of pressuretherein and the more nearly positive becomes therefore the transmissionof motion to the percussive member.

The mean pressure of the air within chamber 1l is maintained aboveatmospheric pressure, usually by affording restricted communicationbetween it and chamber 8 which is itself in free communication with asource of supply, as already stated. For this purpose, there may beformed through the piston Q, a passage 12 so small in area vt-hat only avery small quantity of air can pass through it during one stroke of theapparatus. Alternatively, adjustable spring-controlled valves adapted topass air between the two faces of the piston as described in my pendingapplication Serial No. 532090 may be employed.

rlhe cylinder 1 is provided with a water jacket 13 for removing excessheat generated in the air bodies, and in the case of an ore stamp, themore or less warm water passed out from the jacket may be conveyed intothe mortar box 14. To this end, as shown in Fig. l, pipes 15 extend fromthe bottom of the water jacket, by which the water directed into acup-shaped recess 1G in the top of the stamp head 5; whence it passes bypassage 17 and branches 18 to the peripheryT of the stamp head or by abranch 19 to the face thereof. Similarly, in the Fig. Il construction inwhich the jacket 13 surrounds the cylinder 1 formed in the stamp head 5,said passages carry away the water directly from the jacket.

Provision is made in the case of a stamp for adjusting the mean positionof the percussive member to compensate for its wear and that of the dieupon which it works. In the construction shown, the crank 3 andpositively reciprocated member are mounted upon a frame 2O which isadjustable upon a fixed frame 21. Adjustment is effected by such meansas the screw 22, working through a threaded lug 23 on frame 20. 24indicates bolts for clamping frame 20 in position. In the case of astamp in which the stamp stem is the reciprocated member, a furtheradjustment may be arranged, viz. that of the stamp head 5 with respectto its stem 1n Fig. I is illustrated a parallel-sided stem fitting intoa similar socket 26 in the head 5. 27, 2S, are two wedges which areinserted between the stem and the head, and are tapered in oppositedirections. The one 27 tapering downwardly is furnished with a head 29.In securing the head 5, such wedge 27 is fixed by placing a stop underits head 29, wedge 28 being then driven home. Release of the parts whenrequired is effected by driving in the headed wedge 27.

For making connection between the receiver 10 and the cylinder 1 and tosupply water to jacket 13 any suitable connecting means conformable tothe movement of the cylinder relatively to xed parts, may be employed.ln Fig. I there is shown for this purpose a device comprising a pair oflinks 30, 31. Link 30 is pivoted to fixed parts and stands substantiallyvertically or parallel with the direction. of motion of cylinder 1. Link31 is pivoted both to link 30 and to the cylinder 1 and in its meanposition projects substantially perpendicularly from the latter. Saidlinks support flexible piping for conveying the fluids, which piping mayin some cases consist merely of rubber hose; but as shown in thedrawings consists of sections of rigid pipe 32 connected by lengths ofhose 33. A similar system of piping secured to the hidden side of thelinks supplies water from a source 34 to the jacket 13. This arrangementprovides a cheap and effective connection, using hose to afford therequisite flexibility without causing thrashing or undue liexure of thesame.

In Fig. Il water is supplied to the jacket 13 through a pipe 35 fixed tothe movable frame Q0 and projecting into the jacket parallel with thedirection of motion of the latter. The air supply is furnished by meansof a hollow guide 36 through which the piston rod 37 passes. Stufingboxes 38 are provided at the ends of the guide 36 and, a supply pipe 39from the receiver 10 is taken to the interior thereof. A passage 40 isformed through the piston rod 37 which passage communicates at its lowerend with chamber 8 and opens at 41 in the side of the rod at such aposition as always to communicate with the hollow interior of the guide36.

The stamp head 5 works through a guide 4Q, and to avoid lubricant, usedin the guide, dropping into the mort-ar box 14 and so impairingmetallurgical operations, the head is formed with an enlarged upper part43 which works in the guide. The junction of said enlarged. part withthe relatively reduced lower part of the head is undercut to provide aprojecting lower edge 44. Such edge throws excess lubricant clear of theopening 45 through which the lower part of the head enters the mortarbox; such lubricant being conveniently collected in an annular trough46.

What 1 claim and desire to secure by Letters Patent is :d

1. A structure comprising in combination a rcciprocable cylinder member,a second rcciprocable member furnished with a piston working in saidcylinder, one of said members being provided with a stamp head, meansfor positively reciprocating one of said members, means for maintaininga body of air at a pressure always higher than that of the atmosphere onone side of the piston, said structure having a restricted passage wayfor maintaining a body of air on the other side of the piston at anaverage pressure higher than that of the atmosphere.

2. A structure comprising in combination, a rcciprocable cylindermember, a second rcciprocable member embodying a piston working in saidcylinder and also a piston rod, one of said members being providedpressure higher than that of the atmoswith a stamp head, means formaintaining phere. 10 on the side of the piston unoccupied by the Intestimony whereof I aiiix my signature piston rod a permanent body of'air at a in presence of tWo Witnesses.

pressure always higher than that of the at- HANS CHARLES BEHR. mosphere,said structure having a restricted Witnesses: passage Way formaintaining a body of air WESLEY E. JOHN,

on the other side of the piston at an average C. B. HENDERSON.

Copies of this patent may be obtained for ve cents each, by addressingthe Commissioner of Patents, Washington, D. C.

